MyBatis第一个程序

CREATE DATABASE `mybatis`;
USE `mybatis`;
DROP TABLE IF EXISTS `user`;
CREATE TABLE 
`user` (  `id` int(20) NOT NULL,
`name` varchar(30) DEFAULT NULL,  
`pwd` varchar(30) DEFAULT NULL,  PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert  into `user`(`id`,`name`,`pwd`) values (1,'狂神','123456'),(2,'张 三','abcdef'),(3,'李四','987654');

<dependency>
<groupId>org.mybatis</groupId>    <artifactId>mybatis</artifactId>    <version>3.5.2</version> 
</dependency> 
<dependency>    
<groupId>mysql</groupId>    <artifactId>mysql-connector-java</artifactId>    <version>5.1.47</version> 
</dependency>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/zang/dao/UserMapper.xml"/>
    </mappers>
</configuration>

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
//sqlSessionFactory --> sqlSession
public class MybatisUtils {
    private static SqlSessionFactory sqlSessionFactory;
    static{
        try {
            //使用Mybatis第一步：获取sqlSessionFactory对象
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //既然有了 SqlSessionFactory，顾名思义，我们就可以从中获得 SqlSession 的实例了。
    // SqlSession 完全包含了面向数据库执行 SQL 命令所需的所有方法。
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}

public class User {       
 private int id;  //id   
 private String name;   //姓名   
 private String pwd;   //密码        
 //构造,有参,无参    //set/get    //toString()     }

import com.kuang.pojo.User; import java.util.List;
public interface UserMapper {    
List<User> selectUser(); 
}

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper        
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"        "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.zang.dao.UserMapper">  <select id="selectUser" resultType="com.zang.pojo.User">    
select * from user  
</select> 
</mapper>

@Test
    public void test() {
        //第一步：获得SqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        try {
            //方式一：getMapper
            UserMapper userDao = sqlSession.getMapper(UserMapper.class);
            List<User> userList = userDao.selectUser();
            for (User user : userList) {
                System.out.println(user);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //关闭SqlSession
            sqlSession.close();
        }
    }

<build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>